Ethylenically unsaturated azidoformates



United States Patent 3,369,030 ETHYLENICALLY UNSATURATED AZIDOFORMATESNorman C. MacArthur, Avondale, Pa., assignor to Hercules Incorporated,Wilmington, Del., a corporation of Delaware No Drawing.Continuation-in-part of applications Ser. No. 417,469, Dec. 10, 1964,and Ser. No. 475,232, July 27, 1965. This application Nov. 22, 1966,Ser. No. 596,053

6 Claims. (Cl. 260-349) ABSTRACT OF THE DISCLOSURE Ethylenicallyunsaturated compounds containing 1-5 azidoformate groups, such as themonoazidoformate of the triallyl ether of pentaerythritol, themonoazidoformate of 2-hydroxyethyl methacrylate, and oleyl azidoformate,are described. These compounds are useful in film-forming compositions,as tire cord adhesives, and can be homopolymerized and copolymerized.

This application is a continuation-in-part of my application Ser. No.417,469, filed Dec. 10, 1964, now abandoned, and of my application Ser.No. 475,232, filed July 27, 1965.

This invention relates to azidoformates and, more particularly, toazidoformates containing at least one ethylenically unsaturated group.

The azidoformates of this invention are compounds having the formulawhere R is an organic radical containing ethylenic unsaturation and x isa number from 1 to 5, and preferably from 1 to 3. The ethylenicallyunsaturated group con tained in R preferably has at least one hydrogenatom attached to a carbon atom alpha to the ethylenic unsaturation. Thisunsaturated group can be a vinylidene group (H C=C such as occurs whereR is vinyl, vinylalkyl (such as allyl, 3-butenyl, 4-pentenyl, 2-methyl-3-butenyl, 2-chloromethyl-3-butenyl, etc.),. vinylcycloalkyl (such as4-vinylcyclohexyl) or vinylaryl (for example, 0-, mand p-vinylphenyl andZ-Vinylnaphthyl, and haloor alkyl ring substituted derivatives thereofsuch as vinylchlorophenyl), and other vinylidene groups such as where Ris methallyl, 2-ethylallyl, 3-methyl-3-butenyl, 2,3-dimethyl-3-butenyl,isopropenylphenyl, etc.; a vinylene group (-CH=CH), such as where R ispropenyl, Z-butenyl, l-butenyl, 2-pentenyl, cyclohexenyl,dicyclopentadienyl, 2-phenylethenylene, and as found in the alkenylfragments of such acids as oleic, linoleic, linolenic, licanic oreleostearic acids and the like; a substituted vinylene group of theformula HC=C such as where R is l-isobutenyl or Z-phenylpropenyl, etc.;a fully substituted vinylene group of the formula C C such as where R is2,3-dimethyl-2-butenyl, 2,3-dimethyl-2- pentenyl, or2,3-dirnethyl-2-cyclohexenyl, etc.; or a radical of the formula (R0),,Z, where R is R as defined above or is acrylyl or methacrylyl, Z isthe inert residue of a saturated aliphatic alcohol having a minimumfunctionality of 2, and n is the functionality of Z minus x where x isas defined above and n is at least 1. Preferred alcohols from which Zcan be derived include the dihydric alcohols such as ethylene glycol,tri-methylene glycol, and hexamethylene glycol; trihydric alcohols suchas glycerol and the trimethylol alkanes such as trimethylol propane;tetrahydric alcohols such as pentaerythritol; and the like.

Exemplary of. the ethylenically unsaturated azidoformates of thisinvention are azidoformates having the formulae:

where R is an alkenyl, cycloalkenyl, alkenylaryl and alkenylcycloalkylradical and contains 2 to 12 carbon atoms, as, for example, themonoazidoformate of allyl alcohol, the monoazidoformate of methallylalcohol, oleyl azidoformate, linoleyl azidoformate, eleostearylazidoformate, the monoazidoformate of 0-, m-, and phydroxystyrene, themonoazidoformate of a-vinylbenzyl alcohol, the monoazidoformate of4-vinylcyclohexanol, the monoazidoformate of cyclohexenyl alcohol, andthe monoazidoformate of 2-vinyl-ot-naphthol;

mitoltfltmtlotm amt/An,

where R is hydrogen or methyl; R R R R R and R are each hydrogen oralkyl groups of 1 to 4 carbon atoms and may be alike or diiferent; n, m,and p are 0 to 6 and the sum of n, m, and p is 2 to 6, as, for example,the monoazidoformate of Z-hydroxyethyl acrylate, the monoazidoformate of3-hydroxy-n-propyl acrylate, the monoazidoformate of Z-hydroxy-n-propylacrylate, the monoazidoformate of 4-hydroxybutyl acrylate, themonoazidoformate of S-hydroxyamyl acrylate, the monoazidoformate of6-hydroxyhexyl acrylate, the monoazidoformate of Z-hydroxyethylmethacrylate, the monoazidoformate of 3-hydroxy-n-propyl methacrylate,the monoazidoformate of Z-hydroxy-n-propyl methacrylate, themonoazidoformate of 4-hydroxybutyl methacrylate, the monoazidoformate ofS-hydroxyamyl methacrylate, and the monoazidoformate of 6-hydroxyhexylmethacrylate;

(3) R R R o O t anon,

Tait/Aw,

where R is an alkenyl radical containing 2 to 4 carbon atoms or analkenoyl radical containing 2 to 18 carbon atoms; R R R R R and R areeach hydrogen, alkyl (e.g., methyl and ethyl), methylol,

o H 0 ON:

or -CH O--Y where Y is an alkanoyl or alkenoyl radical containing 3 to18 carbon atoms; and n, m, and p are 0 to 6 and the sum of n, m, and pis 2 to 6; as, for example, the monoazidoformate of pentaerythritol dioleate, the bisazidoformate of pentaerythritol dioleate, themonoazidoformate of ethylene glycol monovinyl ether,

the monoazidoformate of propylene glycol monovinyl I ether, themonoazidoformate of butanediol monovinyl ether, the monoazidoformate ofhexylene glycol monovinyl ether, the monoazidoformate of the allyl etherof ethylene glycol, the monoazidoformate of the allyl ether of1,3-propylene glycol, the monoazidoformate of the monovinyl ether of1,2-propylene glycol, the monoazido- 3 formate of the monoallyl ether oftrimethylol propane, the monoazidoformate of the monoallyl ether ofpentaerythritol, the monoazidoforrnate of the diallyl ether of glycerol,the monoazidoformate of the diallyl ether of trimethylol ethane, themonoazidoformate of the diallyl ether of trimethylol propane, themonoazidoformate of the diallyl ether of pentaerythritol, themonoazidoformate of the triallyl ether of pentaerythritol, thebisazidoformate of the diallyl ether of pentaerythritol, and thetrisazidoformate of the allyl ether of pentaerythritol;

where R is an alkenyl radical containing 2 to 4 carbon atoms, 12 is 1 to2, and m is at least 1, as, for example,

the monoazidoformate of diethylene glycol monovinyl ether, themonoazidoformate of triethylene glycol monovinyl ether, and themonoazidoformates of other polyethylene glycol monovinyl ethers; and

(5) other aziodoformates such as the monoazidoformate of2-vinyl-5,5-bis(hydroxymethyl)-1,3-dioxane, the monoazidoformate of theallyl ether of butenediol, the trisazidoformate of dipentaerythritoltritungate, the trisazidofor mate of the monoallyl ether ofdipentaerythritol, the trisazidoformate of the diallyl ether ofdipen'taerythritol, the trisazidoformate of the triallyl ether ofdipentaerythritol, the tetrakisazidoformate of the monoallyl ether ofdipentaerythritol, the tetrakisazidoformate of the diallyl ether ofdipentaerythritol, the pentakisazidoformate of the monoallyl ether ofdipentaerythritol, the polyazidoformates of the vinyl or allyl ethers ofmannitol, and the like.

The azidoformates of this invention can be prepared in various ways, as,for example, by reacting a compound containing at least one ethylenicdouble bond, having at least one hydrogen on a carbon alpha thereto, andat least one reactive hydroxyl group, with phosgene, and then reactingthe chloroformate resulting from that reaction with an excess, i.e.,from about 1.05 moles to about moles per equivalent of chloroformate ofan alkali azide. These reactions are illustrated by the followingequations:

model x(NaN3) moiiNax x(NaOl) where R and x are as defined above.Exemplary of compounds containing at least one ethylenic double bondwith hydrogen alpha thereto and at least one reactive hydroxyl groupwhich can be used to form the azidoformates of this invention are allylalcohol; hydroxyalkyl acrylates such as hydroxyethyl acrylate,hydroxypropyl acrylate, and the like; hydroxyalkyl methacrylates such ashydroxyethyl methacrylate, hydroxypropyl methacrylate, and the like;alcohols derived from long chain unsaturated acids such as oleylalcohol, linoleyl alcohol, and eleostearyl alcohol, and the like;partial esters of unsaturated acids and polyols such as pentaerythritoldioleate and the like, and alcohols derived from and partial esters ofpolyols with the mixtures of unsaturated fatty acids obtained fromnaturally occurring oils such as tung oil, linseed oil, soybean oil,cottonseed oil, and the like; the monovinyl ethers of glycols such asethylene glycol monovinyl ether, propylene glycol monovinyl ether,butanediol monovinyl ether, diethylene glycol monovinyl ether andhexylene glycol monovinyl ether; the allyl ethers of glycols such as theallyl ether of ethylene glycol, the allyl ether of propylene glycol, theallyl ether of butanediol, the allyl ether of butenediol, and the allylether of hexylene glycol; the monoallyl ether of glycerine; themonoallyl ethers of trimethylolalkanes such as the monoallyl ether oftrirnethylolethane, the monoallyl ether of trimethylolpropane, themonoallyl ether of pentaerythritol; the monoacetals of acrolein andpentaerythritol such as 2-vinyl-5,5-bis(hydroxymethyl)-1,3-dioxane; the0-, m-, and p-hydroxystyrenes; ring substituted derivatives of thehydroxystyrenes; and the like. The diallyl ethers of trihydric alcohols,such as glycerine, trimethylolethane and trimethylolpropane, mixturesthereof with the corresponding monoallyl ethers and the diand triallylethers of pentaerythritol, as well as mixtures thereof with each otherand with the monoallyl ethers, are also suitable.

Before describing the invention in greater detail, the followingexamples are presented to illustrate the preparation of the newazidoformates. All parts and percentages in these and all the otherexamples set forth herein are by weight unless otherwise indicated.

Example 1 To a slurry of 346 parts of phosgene, 140 parts of calciumcarbonate and 668 parts of methylene chloride maintained at 10 C. wereadded dropwise over 45 minutes 325 parts of 2-hydroxyethyl methacrylate,and the reaction mixture was agitated for 1.5 hours at 0 C. and then wassparged with nitrogen for 1 hour. The resulting chloroformate wasaspirated under vacuum for 1 hour and then was filtered while stillcold. The solid was washed with methylene chloride and the filtrate andwashings were concentrated under vacuum to give 266 parts (55% yield) ofchloroformate as a yellowish oil.

To a slurry of 192 parts of sodium azide in 500 parts of water was addeddropwise with agitation the above chloroformate dissolved in 1000 partsof methylene chloride. The reaction mixture was agitated and maintainedat room temperature for 45 hours. Then the methylene chloride layer wasseparated and washed several times with water to remove anywater-soluble impurities and was dried over sodium sulfate. Theazidoformate product was isolated by removing the methylene chlorideunder vacuum. The monoazidoformate of Z-hydroxyethyl methacrylate, whichwas obtained as a straw-colored oil (240 parts; 87% yield based on thechloroformate), showed by infrared analysis of the theoretical amount ofunsaturation present and 84% of the theoretical azidoformate groupspresent.

Example 2 To a slurry of 223 parts of phosgene, 100 parts of calciumcarbonate and 400 parts of methylene chloride maintained at 10 C., 384parts of commercial triallyl ether of pentaerythritol, having an averagedegree of substitution greater than about 2.8, were added dropwise over1.5 hours, and the reaction mixture was agitated for an additional 3.5hours. Excess phosgene was sparged from the reaction mixture withnitrogen, the reaction mixture was then filtered to remove salts, andthe filtrate was aspirated under vacuum to remove the methylene chlorideand give 446 parts (93% yield) of the chloroformate of triallyl ether ofpentaerythritol as an oil.

To a slurry of 216 parts of sodium azide in 400 parts of water was addeddropwise with agitation 440 parts of the above ehloroformate dissolvedin 400 parts of methylene chloride. The reaction mixture was agitatedvigorously, was maintained at room temperature for approximately 3 days,and then was refluxed for 5 hours.

The methylene chloride layer was next separated, was washed severaltimes with water to remove any watersoluble impurities, and then wasdried. The product, the monoazidoformate of the triallyl ether ofpentaerythritol, was isolated as a deep yellow oil in 81% yield, the oilcontaining 0.383 gram of solid per cubic centimeter. Analysis forhydroxyl, terminal methylene, azide groups, total nitrogen, and chlorinegave the following percentage values, as compared with the theoreticalvalues:

Found: OH, 0.2%; CH 11.5%; N 11.1%; nitrogen, 10.0%; chlorine, nil.Calculated for C H O N OH, 0%; CH 12.9%; N 12.9%; nitrogen, 12.9%;chlorine, 0%.

5 Example 3 To a slurry of 0.4 mole of phosgene maintained at 10 C. wasadded dropwise over a period of 20 minutes 0.2 mole of oleyl alcohol.This mixture was stirred at C. for an additional 6 hours, after whichtime the reaction mixture was sparged with nitrogen and placed under areduced pressure to remove the excess phosgene. The resulting productwas 66 parts of oleyl chloroformate in the form of a clear oil.

A solution of 60 parts of the above oleyl chloroformate in 200 parts byvolume of methylene chloride was stirred rapidly with a solution of 35.5parts of sodium azide and 80 parts of water. This stirring was continuedfor days at room temperature, and the organic layer was then separated,washed with water, and dried over sodium sulfate. The resulting productwas filtered, washed with methylene chloride, and yielded 325 parts byvolume of a solution of oleyl azidoformate. A portion of the solvent wasremoved, leaving the azidoformate in the form of a yellow oil. Analysisof the product for hydroxyl, nitrogen, and unsaturation content was asfollows:

Found: OH, 0.04%; nitrogen, 11.1%; HC=CH, 7.6%. Theoretical content ofoleyl azidoformate: OH, 0%; nitrogen, 12.5%; HC=CH, 7.7%.

Example 4 A flask containing 84.2 parts of tung oil acids was flushedwith carbon dioxide and then arranged so that a slow stream of carbondioxide gas moved continuously through the apparatus. The tung oil acidswere then heated to a temperature of 200 C., with stirring, over aperiod of about one-half hour, and 25.4 parts of dipentaerythritol wereadded thereto slowly in the absence of air. A clear, amber solutionresulted, which was held at 200 C., with stirring, until its acid numberwas less than 5 (about 2-3 hours). The resulting product was a viscousliquid with an average of 3 hydroxyl groups per mole. This product wascooled to C. and maintained at that temperature while 60 parts ofphosgene was added thereto in small amounts over a period of 30-45minutes. The temperature of the reaction mixture was then raised to 0 C.and the product was stirred for 6 hours, after which it was allowed towarm to room temperature. The excess phosgene was allowed to escape thereaction mixture during this warming. The resulting product was thechloroformate of dipentaerythritol tritungate. This chloroformate wasdissolved in 300 parts by volume of methylene chloride and was thenstirred with a solution of 38.4 parts of sodium azide in 90 parts ofwater for 5 days at room temperature. The organic layer was thenseparated, washed with water, and dried over sodium sulfate. Theresulting product analyzed on the average for the trisazidoformate ofdipentaerythritol tritungate.

Example 5 a period of 1 hour to a slurry of 147 parts of phosgene,

55 parts of calcium carbonate, and 280 parts of methylene chloride, and116 parts (60% yield) of the chloroformate was obtained as a yellowishoil. The above chloroformate, dissolved in 450 parts of methylenechloride, was next added dropwise with agitation to a slurry of 77 partsof sodium azide in 200 parts of water and the agitation continued for 24hours at room temperature. The azidoformate product was then separated,dried, and isolated according to the procedure of Example 1. Themonoazidoformate of diethylene glycol monovinyl ether which was obtainedas a straw-colored oil (171 parts; 85% yield based on the chloroformate)was confirmed by an infrared spectrum which showed strong absorption at2140 cm.

Since the azidoformates of this invention are monomers 6 which containethylenic unsaturation, they can be converted into homopolymers rangingfrom low to high molecular weight polymers by polymerizing the monomerunder conditions which do not destroy the azidoformate grouping, usuallyusing conventional redox catalysts, such as cobalt-cyclohexanoneperoxide or iron-benzoin-cumene hydroperoxide at room temperature, orsuch free radical initiators as acetyl peroxide, azobisisobutyronitrile,benzoyl peroxide, and the like, between room temperature and about C.Preferably, the homopolymers comprise from 10 to 1000, and mostpreferably from 100 to 500 repeating units of the monomer.

The following example illustrates the preparation of a homopolymer ofthe azidoformate of 2-hydroxyethyl methacrylate. The molecular weight ofthe homopolymer is shown by the reduced specific viscosity (RSV), bywhich is meant the sp/C determined on a 0.1% solution of the polymer ina given solvent at a given temperature.

Example 6 A polymerization tube was charged with 25 parts of an ethylenedichloride solution containing 2.45 parts of the azidoformate of2-hydroxyethyl methacrylate prepared in Example 1 and 0.12 part ofbenzoyl peroxide. The tube was capped, and then was evacuated and filled3 times with nitrogen.- Hypodermic needles were inserted into the tubeso that a stream of nitrogen could be passed into and out of the tubecontinuously. The tube and contents Were then heated to 70 C. and heldthere with agitation for 3 hours, after which the solution was permittedto cool to room temperature overnight. The cooled solution was addeddropwise to 8 to 10 volumes of stirred hexane to precipitate the polymerand the polymer was collected and dried for 3 hours in vacuo at 30 C.The polymeric monoazidoformate of Z-hydroxyethyl methacrylate wasrecovered in 51% conversion, had an RSV of 0.14 as determined inethylene dichloride at 25 C., and on analysis contained 18.88% nitrogen(calculated for C H O N 20.6%) after correction for purity of themonomer.

The azidoformates of this invention can also be converted intocopolymers having molecular weights ranging from low to high bypolymerizing a mixture of the azidoformate and at least one otherethylenically unsaturated monomer under conditions which do not destroythe azidoformate grouping using, if desired, conventional redoxcatalysts or free radical initiators. Thus, compounds containing atleast one vinyl, vinylidene, or vinylene group ordinarily can becopolymerized with the azidoformate. Suitable monomers include, forexample, olefins such as ethylene, trichloroethylene,1,2-dichloropropene-Z; vinyl nitriles such as acrylonitrile andmethacrylonitrile; vinyl esters such as vinyl acetate, vinyl carbazole,vinyl chloride, vinylidene chloride, allyl acetate, allyl chloride,allyl chloroacetate, methallyl acetate, methallyl chloride, isopropenylacetate; diolefins such as butadiene and chloroprene; alkenylaryls suchas styrene, the methylstyrenes, o-, m-, or p-chlorostyrene,2,5-dichlorostyrene, pentachlorostyrene, mor p-bromostyrene.p-iodostyrene, p-cyanostyrene, p-methoxystyrene, andp-dimethylaminostyrene; diethyl fumarate; diethyl maleate; maleicanhydride; the alkyl acrylates such as methyl acrylate and the higheralkyl esters, isobornyl acrylate; the u-chloroacrylates such as methylu-chloroacrylate and the higher alkyl esters, fi-chloroethyl acrylate;the methacrylates such as methyl methacrylate and the higher alkylesters, isobornyl methacrylate; methyl vinyl ketone; 2-vinylpyridine;and the like, as well as an azidoformate of this invention which isdifferent from the other azidoformate.

The following examples illustrate the preparation of azidoformatecopolymers using either the azidoformate of 2-hydroxyethyl methacrylateprepared in Example 1 or the azidoformate of the triallyl ether ofpentaerythritol prepared in Example 2. The molecular weight of thecopolymers is shown by the reduced specific viscosity, as defined above.

Example 7 Into a reaction vessel charged with:

Parts by weight a-Methylstyrene 78 Ethyl acrylate 21 Azidoformate of2-hydroxyethyl methacrylate (dissolved in methylene dichloride) 5 Water200 Sodium la'uryl sulfate 6 FeSO -7H O 0.020 Sodium ethylenediaminetetraacetate 0.029 Sodium formaldehyde sulfoxylate 0.36 tert-Dodecylmercaptan 0.1

and flushed 3 times with nitrogen, there was injected 0.13 part byvolume of a 56% solution of p-menthane hydroperoxide. The mixture wasagitated at 25 C. for 3 hours under nitrogen, and then was shortstoppedby adding 9 parts of a 3% solution of 2,5-di-tert-amylhydroquinone inbenzene. The polymeric latex was coagulated by adding it dropwise to 10volumes of methanol, and then the coagulum was collected and wasdissolved in sufficient toluene to give approximately 10% solids. Thesolution was filtered and the filtrate was added dropwise to 10 volumesof stirred methanol to reprecipitate the polymer. The product wascollected and air-dried for 72 hours, giving a terpolymer ofu-methylstyrene, ethyl acrylate, and the azidoformate of Z-hydroxyethylmethacrylate which weighed 31 grams, contained 1.2% nitrogen, and had anRSV of 1.2 determined in ethylene dichloride at 25 C.

Example 8 A polymerization tube was charged with 10 parts of butylmethacrylate, 0.5 part of the azidoformate of the triallyl ether ofpentaerythritol (dissolved in 1.6 parts of ethylene dichloride), 20parts of benzene and 0.03 part of a,a-azobis(isobutyronitrile). Amagnetic stirring bar was inserted into the tube and the tube was closedand was flushed 3 times with nitrogen. The charge was then heated, withstirring, and maintained at 65 C. for 4 hours. Total solidsdetermination based on the cooled solution indicated 50% conversion tocopolymer. The isolated product, a copolymer of butyl methacrylate, andthe azidoformate of the triallyl ether of pentaerythritol, had an RSV of0.3 determined in ethylene dichloride at 25 C. and contained 0.3%nitrogen.

As was mentioned above, the azidoformates of this invention are usefulin coating compositions. They can be used as such with conventionalfilm-forming compositions or can be homopolymerized or copolymerizedwith at least one other monomer as demonstrated above and used eitheralone as the essential film-forming ingredient or in combination withother polymeric film-forming materials. In either case, theazidoformates can be incorporated with the other coating ingredients inany desired fashion. For example, they can be uniformly blended with theother ingredients by simply milling on a conventional rubber mill attemperatures below which any appreciable decomposition of theazidoformate occurs, or they can be dissolved in a solution of the otheringredients. By either means, the azidoformate is distributed throughoutthe composition. The azidoformate can also be applied as a coating to asubstrate and then topcoated with a conventional polymeric coatingcomposition. Other means of intimately associating the azidoformate withthe other coating ingredients will be apparent to those skilled in theart.

The azidoformates of the present invention are particularly useful withsuch film-forming polymers as the hydrocarbon polymers such aspolyethylene, polypropylene, polystyrene, styrene-butadiene rubber,butyl rubber, natural rubber, polyisobutylene, ethylene-propylenecopolymer, cis-l,4polyisoprene, ethylene-propylene-dicyclopentadieneterpolymers, and the like, as well as the nonhydrocarbon polymers suchas sulfochlorinated polyethylene, poly(vinyl acetate), poly(vinylchloride), poly- (vinylidene chloride), poly( ethylene oxide), poly[3,3-bis- (chloromethyl) oxetane], butadiene-acrylonitrile copolymer,'etc., and blends ofthese polymers with each other or hydrocarbonpolymers.

Coating compositions containing the azidoformates can be applied to thesubstrate in any desired fashion, as, for example, by coating thesubstrate with a dispersion or solution of the coating in a suitablediluent using conventional techniques. No matter how the azidoformate isassociated with other polymeric film-forming materials and/ or thesubstrate, upon subsequent heating to a temperature above thedecomposition point of the azidoformate, modification is effected at theinterfaces of the azidoformate and the other materials and improvedadhesion results. The temperature, which is above the decompositiontemperature of the azidoformate and to which the azidoformate-containingcoatings can be heated, varies over a wide range, but, in general, willbe in the range of from about 70 C. to about 350 C. Various amounts ofthe azidoformate can be used, the optimum amount depending upon theamount of modification desired, the specific azidoformate compoundemployed, etc. For example, in some cases, such as in certain filmapplications, it may be desirable to merely add a sufficient amount ofazidoformate to improve adhesion without materially affecting itssolubility. In general, the amount added, based on the weight of thecoating, will be from about 0.01% to about 20%.

The following examples are presented to illustrate the use of the newazidoformates in adhering coatings.

Examples 9-13 Various coating formulations were prepared by physicallymixing parts of stereoregular polypropylene having a birefringentmelting point of 168 C. and an RSV of 2 to 3 measured indecahydronaphthalene at C., 100 to 200 parts of a hydrocarbon mixtureboiling in the range of to 265 C., 0.5 part of the reaction product of 1mole of crotonaldehyde and 3 moles of 3-rnethyl- 6-tert-butylphenol and0.25 part of dilaurylthiodipropionate with from 0 to 5 parts (solidsbasis) of the azidoformate of the triallyl ether of pentaerythritolprepared in Example 2. Coatings (final thickness of 0.7 mil) were castfrom these formulations onto phosphated steel panels using a 5-milknife, and the coatings were fused, while wet, at about 210 C. for 5minutes, were quenched, and then were tested for adhesion.Crosshatch-adhesion of the coatings to the panels was evaluated bycrosshatching a l-square-inch area of the surface of a coated panel withrazor blade cuts inch apart and at right angles to each other, applyinga strip of conventional transparent pressure-sensitive cellophane" tapeover the crosshatched area with sufficient pressure to assure completeadhesion,

. jerking the tape from the surface, and observing What part, if any, ofthe coating was removed by the tape. In this test, a rating of good wasassigned if no coating was stripped from the panel; a rating of fair ifless than 25% of the coating was stripped; a rating of poor if more than25 but not all of the coating was stripped; and a rating of very poor ifall of the coating was stripped from the panel. Peel adhesion wasevaluated by making parallel cuts /z-inch apart through the coating tothe panel, making a single cut at right angles to the parallel cuts, andthen manually lifting and peeling the coating from the panel. Adhesionwas rated good if the coating peeled with stretching or breaking, fairif it peeled with some noticeable resistance, and poor if it peeledwithout noticeable effort. The amount of azidoformate in eachformulation and the results of the adhesion tests for each are recordedbelow in Table I.

TABLE I Azidoiormate Adhesion Example No. (parts by weight) crosshatchPeel 9 Poor Poor.

0. 5 Good Good. 1. .do Do. 2. -do Do. 5. 0 do Do.

The procedure of Examples -13 was repeated except that unmodifiedtriallyl ether of pentaerythritol was substituted for the azidoformate.In each case, the adhesion of the coating to the panel, as determined bythe crosshatch and peel tests, was poor.

Example 14 A portion of the solution of the monoazidoforrnate of thetriallyl ether of pentaerythritol prepared in Example 2 was diluted to10% solids with xylene and was sprayed as a primer coating on phosphatedsteel panels. The sprayed panels were air-dried for 10 to minutes andthen were topcoated by casting an organosol containing 100 parts ofpolypropylene having an RSV of 2.3 and a particle size of 30 to 50microns, 0.5 part of the reaction product of 1 mole of crotonaldehydeand 3 moles of 3-methyl-6-tert-buty1phenol and 0.25 part ofdilaurylthiodipropion-ate dispersed in 100 to 200 parts of a hydrocarbonmixture boiling in the range of 180 to 265 C. The panels were then bakedfor 5 minutes at 210 C. and quenched. The cross-hatch and peel adhesionof the coatings to the panels of this example were rated as good whereascontrol panels prepared in the same manner, except that the primercoating was omitted, were rated as poor. At the end of one weeks agingat room temperature, the adhesion of the coatings to the panels wasrechecked and found to be very good.

Example 15 A slurry was prepared from 100 parts of stereoregularpolypropylene having a birefringent melting point of 168 C. and an RSVof 4 to 5 determined in decahydronaphthalene at 135 C., 267 parts ofmethylene dichloride and 5 parts (solids basis) of the monoazidoforrnateof the triallyl ether of pentaerythritol prepared in Example 2. Theslurry was stripped of solvent at 25 C. under vacuum and then was heatedfor 45 minutes at 155 C. to decompose the azidoformate. Next, 0.5 partof the reaction product of 1 mole crotonaldehyde and 3 moles of 3-methyl-6-tert-butylphenol and 025 part of dilaurylthiodipropionatedissolved in 10 parts of acetone were slurried with the modifiedpolymer, the acetone was stripped oil under vacuum at room temperature,and the modified polymer was dried at room temperature overnight. Themodified polymer was formed into an organosol by slurrying 100 parts ofthe polymer with 100 to 200 parts of a hydrocarbon mixture boiling inthe range of 180 to 265 C. and the organosol was applied as a coating tosteel panels which were then baked as in Example 14. The coatingsadhered well, whereas control coatings of an organosol prepared in thesame manner as above, except that polypropylene which had not beentreated with the azidoformate was used in place of the modifiedpolypropylene, adhered poorly to steel, thus again demonstrating theability of the azidoformate to improve substantially the adhesion ofcoatings to substrates.

Example 16 A 20% xylene solution of the homopolymer of the azidoformateof 2-hydroxyethyl methacrylate prepared in Example 6 was cast as acoating onto 4 x 6-inch glass panels with a 5-mil blade, the coating wasair-dried for 15 minutes, and then the dried coating was baked at 150 C.for 30 minutes. The coating was hard and brittle, ad-

hered well to the glass, and was not affected by 30-minute immersion inxylene, indicating that the polymer was cross-linked.

Example 17 A 20% xylene solution of the terpolymer of a-methylstyrene,ethyl acrylate, and the azidoformate of Z-hydroxyethyl methacrylateprepared in Example 7 was cast onto 4 x 6-inch bonderized steel panelsusing a 20-mil blade. The coated panels were air-dried for 15 minutesand then the dried panels were baked for 1 hour at 149 C. The coatingwas 1.4 mils thick, had a Sward hardness of 40, was essentiallyinsoluble in xylene, and adhered well to the panels. A similar coatingof a control polymer of amethylstyrene and ethyl acrylate prepared as inExample 7, except that the azidoformate was omitted, dissolved readilyin xylene.

Example 18 The coating solution of Example 17 was cast with a 3-milblade onto a portion of a 5 x 5 x As-inch polypropylene plaque which hadbeen solvent treated by subjecting the surface to be coated to the hotvapors of re fluxing trichloroethylene for about 5 seconds. Anotherportion of the same plaque was similarly coated except that a solutionof the control polymer of Example 17 was used instead of the terpolymer.The plaque was baked for 1 hour at 150 C. and the crosshatch adhesion ofthe coatings to the plaque determined as in Examples 9-13. None of thecoating of the terpolymer of a-methylstyrene, ethyl acrylate and theazidoformate of 2-hydroxyethyl methacrylate was removed from the plaqueby the tape when tested immediately after removal from the oven, warm,or at room temperature, whereas about of the coating of the controlpolymer of ot-methylstyrene and ethyl acry-late was stripped from theplaque when tested hot from the oven, about 10 to 20% removed when warm,and a slight amount removed at room temperature.

methacrylate and the azidoformate of the triallyl ether ofpentaerythritol prepared in Example 8 was knife-cast as a coating onphosphated steel panels and the coating was baked for 30 minutes at C.The coating was insoluble in xylene, indicating that the copolymer wascross-linked.

The azidoformates of this invention are also useful for coating fibersto improve their adhesion to rubber, as, for example, for the treatmentof polyester tire cord. Coating compositions containing theazidoformates can be applied to the surface of the fiber by conventionalmeans, for example, by dipping, spraying, brushing, or running the fiberover a coated roll with a dispersion or solution of the azidoformate ina suitable diluent. Any inert organic diluent or water can be used.After the azidoformate is applied to the substrate, the coated substrateis heated to a temperature above the decomposition point of theazidoformate, resulting in modification of the fibrous substrate at theazidoformate substrate interfaces. The decomposition temperature of theazidoformate, to which the azidoformate coated substrates are heated,varies over a wide range. However, this temperature, which is termed thecuring temperature is generally from about 70 C. to about 350 C. for asuflicient time to allow the desired degree of interaction between theazidoformate and the surface of the substrate to occur. Alternatively,the curing step can be deferred until the azidoformatecoated fiber orcor-d has been embedded in rubber. In such case, the azidoformate can beair-dried at room temperature and the interaction between theazidoformate and the substrate effected during vulcanization.

The direct vulcanization of rubber with modified polyester fiber or cordis illustrated by the following examples.

1 1 Examples 20-23 Samples of poly(ethylene terephthalate) tire cordwere immersed for 5 minutes in a 20% methylene dichloride solution ofthe azidoformate of the triallyl ether of pentaerythritol prepared inExample 2, excess solution was drained from the cord, and the sampleswere dried under the following conditions:

Example Coating, Percent Each of the samples was then embedded instyrene-butadiene rubber stock and the rubber vulcanized for 30 minutesat 155 C. The degree of adhesion of the treated cord to the rubber stockwas evaluated by pulling the cord from the vulcanized stock andobserving the type of adhesive failure. The cords of Examples 20 to 23were covered with rubber to the extent of at least 25%, indicating asignificant amount of failure of the rubber-to-rubber bonds as comparedwith rubber-to-cord bonds. Poly (ethylene terephthalate) cord which hadnot been treated with the azidoformate was similarly incorporated in therubber stock and vulcanized. The cord, after pulling from the vulcanizedstock, had less than 1.0% rubber on its surfaces. These results indicatethat the azidoformates improved the adhesion of rubber to poly(ethyleneterepthalate) tire cord.

What I claim and desire to protect by Letters Patent is:

1. An azidoformate selected from the group consisting of ROCN3 where Ris selected from the group consisting of alkenyl,

cycloalkenyl, alkenylaryl, and alkenylcycloalkyl radicals containing 2to 12 carbon atoms;

( R R1 R3 R O \R l. \RJ... \RJ. where R is selected form the groupconsisting of hydrogen and methyl; R R R R R R are selected from thegroup consisting of hydrogen and alkyl groups containing 1 to 4 carbonatoms; n, m, and p are 0 to 6; and the sum of n, m; and p is 2 to 6;

3 R R R O aoltlltlltloa. \t l. \tJ- \ii/.

12 where R is selected from the group consisting of alkenyl radicalscontaining 2 to 4 carbon atoms and alkenoyl radicals containing 2 to 18carbon atoms; R R R R R and R are selected from the group consisting ofhydrogen, alkyl, methylol,

and CH OY where Y is selected from the group consisting of alkanoyl andalkenoyl radicals containing 3 to 18 carbon atoms; and n, m, and p are 0to 6 and the sum ofn, m, andpisZto 6;

(4) r "I H R O LCH: \CH2/n ()Jm CH2 \CHz/n O 0N2 where R is an alkenylradical containing 2 to 4 carbon atoms, n is 1 to 2, and m is a numberwhich is at least 1; and (5) the monoazidoformate of2-vinyl-5,5-bis(hydroxymethyl)-1,3-dioxane, the monoazidoformate of theallyl ether of butene diol, the trisazidoformate of dipentaerythritoltritungate, the trisazidoformate of the mono.- allyl ether ofdipentaerythritol, the trisazidoformate of the diallyl ether ofdipentaerythritol, the trisazidoformate of the triallyl ether ofdipentaerythritol, the tetrakisazidoformate of the monoallyl ether ofdispentaerythritol, the tetralkisazidoformate of the diallyl ether ofdipentaerythriml, the pentakisazidoformate of the monoallyl ether ofdipentaerythritol, the polyazidoformates of the vinyl ethers of mannitolor the polyazidoformates of the allyl ethers of mannitol.

2. The azidoformate of claim 1 which is the monoazidoformate of 2-hydroxyethyl methacrylate.

3. The azidoforma te of claim 1 which is the monoazidoformate of thetriallyl ether of pentae-rythritol.

4. The azidoformate of claim 1 which is oleyl azidoformate.

5. The azidoformate of claim 1 which is the trisazidoformate ofdipentaerythritol tritungate.

6. The azidoformate of claim 1 which is the monoazidoformate ofdiethylene glycol monovinyl ether.

References Cited UNITED STATES PATENTS 3,211,677 10/1965 Feild et al260349 X 3,211,678 10/1965 Robinson 260-349 X 3,211,752 10/1965 Breslow260-349 3,284,421 11/ 1966 Breslow 260349 X JOHN D. RANDOLPH, PrimaryExaminer.

WALTER A. MODANCE, Examiner.

JOHN M. ,FORD, Assistant Examiner.

